CN111628190A - Fuel cell system - Google Patents

Abstract

The invention discloses a fuel cell system, which relates to the technical field of fuel cells and is invented for effectively improving the fuel utilization rate of fuel gas in the whole process and improving the power generation efficiency. The fuel cell system includes a fuel cell assembly; an anode heat exchanger, the anode heat exchanger includes a first port, a second port, a third port and a fourth port, the first port communicates with the second port, and the third port communicates with the first port. The four ports communicate with each other, the first port is used to pass the fuel gas, the second port is communicated with the anode air inlet of the fuel cell assembly, the third port is communicated with the anode air outlet of the fuel cell, and the fourth port is connected through the first shunt pipe and the third port respectively. The second shunt pipe is communicated with the first port; the decarburization and dehydration device, the inlet end of the decarburization and dehydration device is communicated with the second shunt pipe, and the outlet end is communicated with the first port. The fuel cell system of the present invention is used to improve the working performance of the cell.

Description

a fuel cell system

technical field

The present invention relates to the technical field of fuel cells, and in particular, to a fuel cell system.

Background technique

Solid oxide fuel cells use cheaper hydrocarbons such as natural gas and coal combustion synthesis gas as fuel gas to provide hydrogen source, use air as oxygen source, and hydrocarbons are reformed upstream of fuel cell components .

The single-pass fuel utilization rate of the existing SOFC Generally, it will not exceed 85%, so the exhaust gas discharged from the anode outlet of the battery will contain some unused fuel gas (the main components are CO and H ₂ ). The entire fuel utilization rate of the fuel gas (the entire fuel utilization rate refers to the sum of the above-described one-way and cycle, the utilization rate of the fuel gas), so that the chemical energy of the fuel gas can be converted into electrical energy as much as possible.

In the prior art, there is a solid oxide fuel cell power generation system with exhaust gas circulation, which utilizes the fuel exhaust gas to recirculate the fuel exhaust gas in the fuel cell to the inlet of the fuel side of the cell using a circulation pipe and a jet pump. However, the fuel exhaust gas contains a high content of inert gas CO ₂ . After the fuel exhaust gas is mixed with the fuel gas, the flow rate will not only greatly increase, but also the concentration of the combustible gas (CO, H ₂ , CH ₄ , etc.) will be diluted, thereby affecting the chemical reaction in the fuel cell. conduct.

The prior art provides a fuel cell tail gas recycling device, which is provided with an absorption tank filled with a desulfurization and decarburization agent at the fuel inlet. The fuel waste gas is connected to the heat dissipation pipeline and the thermal insulation pipeline and returns to the absorption tank. The thermal insulation pipeline is provided with a valve. When the temperature of the absorption tank is lower than 30 ℃, the thermal insulation pipeline valve is opened. When the temperature of the absorption tank is greater than or equal to 60 degrees, the valve is closed to maintain the temperature of the absorption tank. After removing CO ₂ in the absorption tank, the fuel waste gas enters the fuel cell together with the fresh fuel gas for anode reaction. CO ₂ to avoid the phenomenon of diluting the concentration of combustible gas, however, there are still the following technical problems: 1. The working temperature of the absorption tank is about 60°C, the working temperature of the fuel cell is about 700-800°C, and the outlet of the fuel cell is high temperature The exhaust gas (about 800°C) must be cooled and then enter the absorption tank. The device dissipates heat from the high-temperature exhaust gas through the heat dissipation pipeline, resulting in serious heat loss, and the heat is not fully utilized. At the same time, the decarbonized exhaust gas needs to be preheated after being mixed with fresh fuel gas to enter the fuel cell. The device is not equipped with any internal heat recovery device, and an external heat source (such as electric heating) needs to be introduced. However, due to the introduction of the low-temperature absorption tank, the power generation efficiency of the entire fuel cell is not greatly improved, but may decrease; 2. The device also ignores the fuel cell inlet water-carbon ratio (calculated by the ratio of oxygen atoms and carbon atoms) If the fuel cell contains CO, CH ₄ and other hydrocarbon fuels, there will be the possibility of coking. Generally, the water-to-carbon ratio of the imported gas should not be lower than 2.0. Supplementation will take away part of the battery heat and thus affect the power generation efficiency of the battery. The desulfurization and decarburization agent in the absorption tank of the device will also remove the water vapor while removing CO ₂ and recycle it back to the fuel cell. The water-to-carbon ratio is far It is far from enough, so additional water vapor needs to be introduced, which will reduce the power generation efficiency.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a fuel cell system, the main purpose of which is to make full use of the fuel exhaust gas of the fuel cell, avoid the phenomenon that CO ₂ in the fuel exhaust gas dilutes the concentration of combustible gas, and fully utilize the heat discharged from the exhaust gas of the fuel cell to ensure The water-to-carbon ratio of the reaction can finally effectively improve the fuel utilization rate of the fuel gas in the whole process and improve the power generation efficiency.

To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

An embodiment of the present invention provides a fuel cell system, including:

a fuel cell assembly for generating electrical energy from fuel gas and oxygen-containing gas;

An anode heat exchanger, the anode heat exchanger includes a first port, a second port, a third port and a fourth port, the first port communicates with the second port, and the third port communicates with the first port Four ports communicate with each other, the first port is used for introducing the fuel gas, the second port is in communication with the anode gas inlet of the fuel cell assembly, and the third port is in communication with the anode gas outlet of the fuel cell communication, the fourth port is respectively connected to the first shunt pipe and the second shunt pipe, and the other end of the first shunt pipe is communicated with the first port;

In the decarburization and dehydration device, the inlet end of the decarburization dehydration device is communicated with the other end of the second branch pipe, and the outlet end of the decarburization dehydration device is communicated with the first port.

The fuel cell system provided by the embodiment of the present invention adopts the anode heat exchanger, that is, the high-temperature fuel exhaust gas discharged from the anode gas outlet of the fuel cell assembly is used for heat exchange with the fuel gas to preheat the fuel gas, so that the fuel gas is fully preheated. The energy of the high-temperature fuel exhaust gas is used to ensure the power generation efficiency of the fuel cell assembly, and it is energy-saving and environmentally friendly. At the same time, one end of the first shunt is connected to the fourth port of the anode heat exchanger, and the other end is connected to the first The port is communicated, and one end of the second shunt is communicated with the fourth port of the anode heat exchanger, and the other end is communicated with the inlet end of the decarburization and dehydration device, and the outlet end of the decarburization dehydration device is communicated with the first port of the anode heat exchanger In this way, the effective components in the fuel waste gas are effectively utilized, the fuel utilization rate of the fuel gas is improved, and the power generation efficiency is improved, and the water-to-carbon ratio of the fuel gas entering the fuel cell assembly is effectively guaranteed.

Optionally, a first flow controller is installed on the first shunt pipe, and the first flow controller is used to control the flow rate of the gas flowing into the first shunt pipe from the fourth port, and the second A second flow controller is installed on the branch pipe, and the second flow controller is used to control the flow rate of the gas flowing into the second branch pipe from the fourth port.

Optionally, the fuel cell system further includes:

a humidity measuring instrument installed at the first port of the anode heat exchanger and used to measure the water content in the fuel gas flowing into the first port;

a processor, the input end of the processor is connected to the humidity measuring instrument, the output end of the processor is respectively connected to the first flow controller and the second flow controller, the processor is used for calculating the actual water-to-carbon ratio of the fuel gas flowing into the first port, and according to the actual water-to-carbon ratio and the preset water-to-carbon ratio, correspondingly adjust the first flow regulator by controlling the first flow regulator The flow rate of the gas in the shunt pipe and the flow rate of the gas in the second shunt pipe are adjusted by controlling the second flow regulator.

Optionally, when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.5 to 2:1, the ratio of the flow rate of the gas in the first branch pipe to the flow rate of the gas in the second branch pipe is 0.9 to 4:1.

Optionally, a cooler is installed at the inlet end of the decarburization and dehydration device.

Optionally, the outlet end of the decarburization and dehydration device is also connected with a purge gas pipe.

Further, the gas flow rate in the purge gas pipe accounts for 5% to 10% of the gas flow rate discharged from the outlet end of the decarburization and dehydration device.

Optionally, the working pressure of the decarburization and dehydration device is 2Mpa to 3Mpa.

Optionally, a first pressurizing device is installed at the outlet end of the decarburization and dehydration device.

Optionally, the fuel cell system further includes:

a cathode heat exchanger, the cathode heat exchanger includes a fifth port, a sixth port, a seventh port and an eighth port, the fifth port communicates with the sixth port, and the seventh port communicates with the sixth port Eight ports are in communication, the fifth port is used to pass into the oxygen-containing gas, the sixth port is in communication with the cathode air inlet of the fuel cell assembly, and the seventh port is in communication with the cathode of the fuel cell assembly The air outlet is connected.

Further, a second supercharging device is installed at the fifth port of the cathode heat exchanger.

Description of drawings

FIG. 1 is a schematic structural diagram of a fuel cell system according to an embodiment of the present invention;

FIG. 2 is a circuit schematic block diagram of a control device in a fuel cell system according to an embodiment of the present invention.

Detailed ways

The fuel cell system according to the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying The device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

The terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

1, an embodiment of the present invention provides a fuel cell system, including: a fuel cell assembly 1, an anode heat exchanger 2 and a decarburization and dehydration device 3, the fuel cell assembly 1 is used to generate electrical energy from fuel gas and oxygen-containing gas ; Anode heat exchanger 2 includes a first port 01, a second port 02, a third port 03 and a fourth port 04, the first port 01 port communicates with the second port 02, the third port 03 communicates with the fourth port 04, The first port 01 is used to introduce fuel gas, the second port 02 is communicated with the anode air inlet of the fuel cell assembly 1, the third port 03 is communicated with the anode air outlet of the fuel cell assembly 1, and the fourth port 04 is communicated with the first The shunt pipe 5 and the second shunt pipe 6, the other end of the first shunt pipe 5 is communicated with the first port 01; the inlet end of the decarburization and dehydration device 3 is communicated with the other end of the second shunt pipe 6, and the The outlet end communicates with the first port 01 .

When the fuel cell system is used to generate electricity, oxygen-containing gas is introduced through the cathode air inlet of the fuel cell assembly 1, and at the same time, the fuel gas is introduced through the first port 01 of the anode heat exchanger 2, and the fuel gas passes through the third port. 03 and the anode air inlet of the fuel cell assembly 1 enter the fuel cell assembly 1, and the incoming fuel gas and the oxygen-containing gas undergo an electrochemical reaction to convert chemical energy into electrical energy. With the continuous introduction of fuel gas and oxygen-containing gas, high-temperature gas can be discharged from the anode gas outlet of the fuel cell assembly 1 (the gas temperature is about 700-800°C). The normal temperature fuel gas undergoes heat exchange to preheat the fuel gas to increase the temperature of the fuel gas to above 400°C, so as to meet the requirements of power generation. Compared with the existing fuel cell system, there is no need to set up a dedicated external heat source, which reduces the manufacturing cost, and has the effect of energy saving and environmental protection.

The high-temperature gas discharged from the anode outlet generally contains water vapor (H ₂ O), carbon dioxide (CO ₂ ), unreacted hydrogen (H ₂ ) and carbon monoxide (CO) generated by the reaction. In order to reuse the unreacted gas hydrogen (H ₂ ) and carbon monoxide (CO), the fuel cell system provided in this embodiment includes a circulation loop to make full use of unreacted hydrogen (H ₂ ) and carbon monoxide (CO), and ultimately improve the overall fuel efficiency of the entire fuel gas At the same time, the water vapor is also conducive to the steam reforming reaction in the fuel cell assembly 1, and also avoids the phenomenon of coking in the fuel cell assembly 1.

After the high-temperature gas discharged from the anode gas outlet is heat-exchanged with the low-temperature fuel gas through the anode heat exchanger 2, the gas discharged from the fourth port 04 (including H ₂ O, CO ₂ , H ₂ , CO and other gases, and the temperature is 300 ℃), in order to prevent the concentration of carbon monoxide and hydrogen from diluting the concentration of carbon monoxide and hydrogen with a large content of water vapor and carbon dioxide, which affects the progress of the electrochemical reaction, and in order to ensure the water-carbon ratio of the fuel gas entering the fuel cell assembly 1, the present invention implements The circulation loop of the fuel cell system provided by the example includes two circulation loops: referring to FIG. 1 , in the first circulation loop, a part of the gas flows into the anode heat exchanger 2 through the first shunt pipe 5, and in the second circulation loop, the rest of the gas passes through the second circulation loop. After the shunt pipe 6, the water and carbon dioxide in the gas are removed through the decarburization and dehydration device 3, and the removed gas flows into the anode heat exchanger 2, that is, the first path will contain water and carbon dioxide. The gas in the fuel cell is mixed with fresh fuel gas, and the second path mixes the gas that does not contain water and carbon dioxide with fresh fuel gas. The purpose of this design is to ensure that water vapor enters the fuel cell assembly 1 for reforming reaction. On the premise, the water-to-carbon ratio of the fuel gas entering the fuel cell assembly 1 can be guaranteed, thereby improving the power generation amount and the power generation efficiency of the fuel cell assembly 1 .

The specific reaction process of the fuel cell system is described below by taking the synthesis gas generated by coal combustion as an example:

The main components of the synthesis gas generated by coal combustion include: _CO , H ₂ , a small amount of _{CH 4} , _{CO 2} and N ₂ . The H ₂ and CO flowing out of the carbon dehydration device 3 are mixed, and after heat exchange with the gas (including H ₂ O, CO ₂ , H ₂ and CO) discharged from the anode gas outlet through the anode heat exchanger 2, it enters through the second port 02 The anode air inlet of the fuel cell assembly 1, at the same time, the air enters the fuel cell assembly 1 through the cathode air inlet of the fuel cell assembly 1, and the oxygen in the air is electrochemically generated with CO, H ₂ , CH ₄ in the fuel gas through the electrolyte react to generate electricity.

The synthesis gas was introduced into the anode of the fuel cell assembly 1 at a flow rate of 252 L/Min, and air was introduced into the cathode of the fuel cell assembly 1 at a flow rate of 6347 L/Min. Analysis of the effect:

If all the gas discharged from the anode gas outlet of the fuel cell assembly 1 passes through the first port 01 of the anode heat exchanger 2, the water to carbon ratio of the fuel gas entering the anode gas inlet of the fuel cell assembly 1 is 3.3, and CO and The concentration of H ₂ is 5.1% and 9.2%, respectively, the power generation efficiency of the stack is 58.6%, the whole fuel utilization rate of the syngas is 95.0%, and the purge gas ratio is 10%;

If all the gas discharged from the anode gas outlet of the fuel cell assembly 1 passes through the first port 01 of the anode heat exchanger 2 after the carbon water is removed from the decarburization and dehydration device 3, the fuel gas entering the anode gas inlet of the fuel cell assembly 1 will have a The water-to-carbon ratio was 0.96, the concentrations of CO and _H2 were 32.2% and 58.1%, respectively, the full-cycle fuel utilization rate of syngas was 93.8%, and the power generation efficiency of the stack was 64.1%.

If 50% of the gas discharged from the anode gas outlet of the fuel cell assembly 1 passes through the first port 01 of the anode heat exchanger 2 after the carbon water is removed from the decarburization and dehydration device 3, the remaining gas passes through the first port 01 of the anode heat exchanger 2. One port 01, the water-to-carbon ratio of the fuel gas entering the anode air inlet of the fuel cell assembly 1 is 2.1, and the concentrations of CO and _H2 are 19.4% and 35.1%, respectively, and the power generation efficiency of the stack is 62.6%. The fuel utilization rate of the whole process is 97.4%.

From the above experimental data, it is obvious that when using the embodiment of the present invention to carry out the electrochemical reaction between syngas and air, the water-to-carbon ratio of the fuel gas entering the anode air inlet of the fuel cell assembly 1 is higher than 2.0, which can effectively prevent the cell Internal coking and carbon deposition, and the overall fuel utilization rate of syngas is significantly higher than the other two cases, and the power generation efficiency of the stack is guaranteed. Therefore, the fuel cell system can effectively improve the overall fuel utilization rate of syngas.

In order to keep the water-to-carbon ratio of the fuel gas entering the anode inlet of the fuel cell assembly 1 always higher than 2.0, when the volume ratio of hydrogen and carbon monoxide in the fuel gas is 1.5-2:1, the first shunt pipe 5 The ratio of the flow rate of the gas in the fuel gas to the flow rate of the gas in the second shunt pipe 6 is 0.9 to 4:1. If the ratio is greater than 4, the water vapor content in the fuel gas will increase. When the water vapor content is high, the corresponding Reduce the concentration of carbon monoxide and hydrogen, and reduce the efficiency of the electrochemical reaction. If the ratio is less than 0.9, it will increase the concentration of CO in the fuel gas and cause a series of carbon deposition and coking processes, which will affect the performance of the stack and cause the decay of the stack. , which may cause system downtime in severe cases. Preferably, when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.6:1, the ratio of the flow rate of the gas in the first branch pipe 5 to the flow rate of the gas in the second branch pipe 6 is 1:1.

When the gas in the first shunt tube 5 flows into the first port 01 of the anode heat exchanger 2, in order to avoid heat loss when the gas flows in the first separation tube 5 and ensure the effective use of heat, the first shunt tube 5 is provided with a heat preservation device. Through the thermal insulation structure, the energy of the gas in the first shunt pipe 5 can be effectively utilized, thereby improving the energy utilization rate of the entire fuel cell system. In an example, the thermal insulation structure may be an thermal insulation layer, and the thermal insulation layer is coated on the outer wall of the first shunt pipe 5 ; in another example, the first shunt pipe 5 is sleeved inside the outer pipe, and the outer pipe and the first shunt pipe 5 are between A vacuum chamber is formed, and the vacuum chamber forms a thermal insulation structure; in addition, the thermal insulation structure can also be other structures.

In order to more accurately control the flow rate of the gas flowing into the first shunt pipe 5, referring to FIG. 1 , a first flow controller is installed on the first shunt pipe 5, and the first flow controller is used to control the flow of the first shunt from the fourth port 24 The flow rate of the gas in tube 5.

In order to control the flow rate of the gas flowing into the second branch pipe 6 more accurately, referring to FIG. 1 , a second flow controller is installed on the second branch pipe 6 , and the second flow controller is used to control the flow into the second branch flow from the fourth port 24 The flow of gas in tube 6.

It should be noted that a total flow controller can be set at the fourth port 04, and the implementable solutions include: for example, a first flow controller is installed on the first branch pipe 5 and a first flow controller is installed at the fourth port 04. The total flow controller; in another example, a second flow controller is installed on the second branch pipe 6 and a total flow controller is installed at the fourth port 04; in another example, the first branch pipe 5 is installed with a first A flow controller, the second flow controller is installed on the second branch pipe 6 . The specific implementation is not limited here, as long as the flow rate of the gas entering the first branch pipe 5 and the second branch pipe 6 can be accurately controlled.

The structures of the first flow controller and the second flow controller may be the same or different. For the convenience of implementation, the first flow controller and the second flow controller with the same structure are preferred.

In some embodiments, the first flow controller includes a first control valve 7 , a first flow meter 15 installed on the first branch pipe 5 , and the first flow meter 15 is used to detect the gas in the first branch pipe 5 . Flow value, the flow rate of the gas flowing into the first branch pipe 5 is controlled by the opening degree of the first control valve 7; the second flow controller includes a second control valve 8, and the second flow rate installed on the second branch pipe 6 The second flow meter 16 is used to detect the flow rate value of the gas in the second branch pipe 6 , and control the flow rate of the gas flowing into the second branch pipe 6 through the opening degree of the second control valve 8 .

For the first control valve 7 and the second control valve 8, a globe valve, a butterfly valve, etc. can be selected.

The first flowmeter 15 and the second flowmeter 16 can be selected from flowmeters resistant to high temperature gas and corrosion, such as differential pressure flowmeters, ultrasonic flowmeters, etc., or mass flowmeters with higher measurement accuracy.

1 and 2 , the fuel cell system further includes: a humidity measuring instrument 13 , which is installed at the first port 01 of the anode heat exchanger 2 and is used to measure the fuel gas flowing into the first port 01 processor 14, the input end of the processor 14 is connected to the humidity measuring instrument 13, and the output end of the processor 14 is respectively connected to the first flow controller (specifically, the first control valve 7) and the second The flow controller (specifically, the second control valve 8) is connected, and the processor 14 is used to calculate the actual water-to-carbon ratio of the fuel gas flowing into the first port 01, and to calculate the actual water-to-carbon ratio and the preset water-to-carbon ratio according to the actual water to carbon ratio. , correspondingly by controlling the first flow regulator to adjust the flow of the gas in the first shunt pipe 5 and by controlling the second flow regulator to adjust the gas flow in the second shunt pipe 6, and the input end of the processor 14 Also connected to the first flow meter 15 and the second flow meter 16 . In specific implementation, through the cooperation of the processor 14, the first control valve 7 and the second control valve 8, the water-to-carbon ratio of the fuel gas flowing into the first port 01 can be precisely controlled, so that the actual water-to-carbon ratio meets the preset requirements. water to carbon ratio.

The decarburization and dehydration device 3 has various structures. For example, a hot potash absorption device can be selected, that is, the gas is washed with a solution containing chemically active substances to remove water and carbon dioxide; another example, pressure swing adsorption can also be selected. The device uses different gases with different adsorption capacities under different partial pressures to adsorb water vapor and carbon dioxide; for another example, MEDA (methyldiethanolamine) can also be selected, that is, the gas is washed by a solution containing chemically active substances , to remove water and carbon dioxide. The specific structure of the decarburization and dehydration device 3 is not limited here, and any structure of the decarburization and dehydration device 3 is within the protection scope of the present invention.

In order to ensure the decarburization and dehydration efficiency of the decarburization and dehydration device 3, the working pressure of the decarburization dehydration device 3 is 2Mpa-3Mpa.

In order to ensure that the gas discharged from the anode gas outlet of the fuel cell assembly 1 can smoothly enter the decarburization and dehydration device 3 without the need for a pressurizing device, the working pressure of the fuel cell assembly 1 is also 2Mpa to 3Mpa, which can simplify the structure. At the same time, when the fuel cell assembly 1 works under 2Mpa to 3Mpa, the power generation voltage and power generation efficiency can be effectively guaranteed.

Usually, the working temperature of the decarburization and dehydration device 3 is 30°C to 60°C, but the temperature of the gas discharged from the fourth port 24 of the anode heat exchanger 2 is about 300°C. A cooler 9 is installed at the inlet end of the carbon dehydration device 3 . That is, the gas flowing out of the fourth port 04 of the anode heat exchanger 2 enters the cooler 9 after passing through the second shunt pipe 6, and passes through the cooling effect of the cooler 9 on the gas, so that the temperature of the gas entering the decarburization and dehydration device 3 is sufficient for decarburization. The working temperature of the dehydration device 3.

In some embodiments, a cooling structure can be provided on the second split pipe 6, and the gas flowing through the second split pipe 6 can be cooled by the cooling structure. A cooling medium is filled between the second separation pipe 6 and the cooling medium forms a cooling structure.

When the gas is discharged from the outlet end of the decarburization dehydration device 3, the gas pressure is relatively small. In order to increase the flow pressure of the gas discharged from the outlet end of the decarburization dehydration device 3, referring to FIG. 1, the outlet end of the decarburization dehydration device 3 is installed There is a first booster device 10 , the inlet end of the first booster device 10 communicates with the outlet end of the decarburization and dehydration device 3 , and the outlet end of the first booster device 10 communicates with the first port 01 of the anode heat exchanger 2 . The first booster device 10 may be a booster pump, a fan or other booster devices.

The gas discharged from the anode gas outlet will be mixed with inert gas, such as nitrogen, argon, etc., in order to prevent the accumulation of inert gas in the entire fuel cell system and affect the electrochemical reaction efficiency, referring to Figure 1, decarburization and dehydration device 3 The outlet end of the reactor is also connected with a purge gas pipe 12, and a trace amount of inert gas in the gas is discharged through the purge gas pipe 12 to ensure reaction efficiency and power generation.

The fuel cell system further includes: a gas recovery device, which is communicated with the decarbonization and dehydration device 3 for recovering carbon dioxide and water removed by the decarbonization and dehydration device 3 . The carbon dioxide and water are collected by the gas recovery unit for use in other chemical units.

1, the fuel cell system further includes: a cathode heat exchanger 4, the cathode heat exchanger 4 includes a fifth port 05, a sixth port 06, a seventh port 07 and an eighth port 08, the fifth port 05 and the sixth port 06 is in communication, the seventh port 07 is in communication with the eighth port 08, the fifth port 05 is used to pass oxygen-containing gas, the sixth port 06 is in communication with the cathode gas inlet of the fuel cell assembly 1, and the seventh port 07 is in communication with the fuel cell assembly 1 The cathode outlet is connected.

During the specific power generation of the fuel cell system, with the continuous introduction of fuel gas and oxygen-containing gas, high-temperature gas (gas temperature is 700-800 ° C) can be discharged from the cathode gas outlet, and the high-temperature gas is in the cathode heat exchanger 4. The incoming normal temperature oxygen-containing gas undergoes heat exchange to preheat the oxygen-containing gas to increase the temperature of the oxygen-containing gas to above 400°C. By arranging the cathode heat exchanger 4, the heat of the high-temperature gas discharged from the cathode gas outlet is effectively utilized, so that no special heating device is required, and the energy consumption of the entire fuel cell system is reduced.

In order to increase the flow pressure of the oxygen-containing gas, referring to FIG. 1 , a second supercharging device 11 is installed at the fifth port 05 of the cathode heat exchanger 4 , and the intake end of the second supercharging device 11 is used for introducing the oxygen-containing gas , the outlet end of the second supercharging device 11 is communicated with the fifth port 05 of the cathode heat exchanger 4 . The second booster device 11 may be a booster pump, a fan or other booster devices.

The fuel cell system provided by the embodiment of the present invention is used to carry out a simulation experiment, wherein the fuel gas is a synthesis gas obtained by a water-gas change reaction, and the oxygen-containing gas is air, and the synthesis gas includes: H ₂ , CO, a small amount of N ₂ and CO ₂ , and the hydrogen-carbon ratio is about 1.6:1. The set operating parameters include:

Battery conversion rate per trip 65% The proportion of gas flow in the first shunt pipe 50% CO₂ Removal Rate of Decarburization and Dehydration Unit 100% H₂0 Removal Rate of Decarburization and Dehydration Unit 100% Purge gas ratio 10%

It should be noted that it is impossible to completely remove CO ₂ and H ₂ O in the actual process. In the low-temperature methanol washing process, CO ₂ and H ₂ O can be removed to ppm and ppb levels. Such a small amount of CO ₂ is necessary for process calculation. The effect is small, so for the convenience of simulation calculation, the removal rate of _CO2 and _H2O is set as 100% here.

Using Aspen Plus software for simulation calculation, the simulation results are:

Water to carbon ratio of anode inlet 2.1 N₂ content of anode inlet 8.3% The power generation efficiency of the battery 62.6% The net electrical efficiency of the system 60.2%

From the simulation results we can get:

1. When the proportion of gas flow in the first shunt pipe is 50%, the water-to-carbon ratio of the fuel gas can reach 2.1, which can effectively prevent coking, that is, by adjusting the gas ratio in the first shunt pipe, the water-to-carbon ratio can be adjusted conveniently and accurately. .

2. In the case of setting 10% purge gas, _N2 accumulation can be well prevented, so that the _N2 content in the fuel gas at the anode inlet is only 8.3%, and there is no large-scale accumulation and dilution of effective gas. Happening.

3. The DC power generation efficiency of the battery can be as high as 62.6%. After deducting the power consumption of the power equipment such as the decarbonization and dehydration device 3 and the booster device, the net power generation efficiency of the system is still 60.2%.

The following comparison table is a comparison table of the simulation results of four fuel cell systems. The first fuel cell system does not include anode tail gas circulation and anode tail gas decarburization and dehydration treatment, and the second fuel cell system does not include anode tail gas. cycle, including anode tail gas decarbonization and dehydration treatment and recycling, the third fuel cell system includes anode tail gas circulation, but does not include anode tail gas decarbonization and dehydration treatment, and the fourth is the fuel cell system provided by the embodiment of the present invention. The above four The fuel cell system generates electricity under the same reaction conditions. The reaction conditions include: the composition of the fuel gas, the one-way fuel utilization rate of the fuel gas, the flow rate of the fuel gas, the working pressure of the stack, the working temperature of the stack, and the purge gas ratio:

The fuel gases used in the above four fuel cell systems are all syngas, wherein the ratio of the main components H2 and CO in the syngas is 1.6:1.

It is shown from the above comparison that the net electrical efficiency of the fuel cell system provided by the embodiment of the present invention has obvious advantages compared with the other three fuel cell systems under the condition that the water-to-carbon ratio meets the requirements. Although the second fuel cell system has higher electrical efficiency, its water-to-carbon ratio is only 0.96, which will cause carbon deposition in the stack and thus affect the performance of the stack.

In the description of this specification, the particular features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (11)

1. A fuel cell system, characterized in that, comprising: a fuel cell assembly for generating electrical energy from fuel gas and oxygen-containing gas; An anode heat exchanger, the anode heat exchanger includes a first port, a second port, a third port and a fourth port, the first port communicates with the second port, and the third port communicates with the first port Four ports are in communication, the first port is used to pass the fuel gas, the second port is in communication with the anode air inlet of the fuel cell assembly, and the third port is in communication with the anode outlet of the fuel cell assembly. The air port is communicated, the fourth port is communicated with the first shunt pipe and the second shunt pipe respectively, and the other end of the first shunt pipe is communicated with the first port; In the decarburization and dehydration device, the inlet end of the decarburization dehydration device is communicated with the other end of the second branch pipe, and the outlet end of the decarburization dehydration device is communicated with the first port. 2 . The fuel cell system according to claim 1 , wherein a first flow controller is installed on the first shunt pipe, and the first flow controller is used to control the flow of the fourth port into the fuel cell system. 3 . The flow rate of the gas in the first shunt pipe, a second flow controller is installed on the second shunt pipe, and the second flow controller is used to control the flow rate of the gas flowing into the second shunt pipe from the fourth port . 3. The fuel cell system according to claim 2, wherein the fuel cell system further comprises: a humidity measuring instrument installed at the first port of the anode heat exchanger and used to measure the water content in the fuel gas flowing into the first port; a processor, the input end of the processor is connected to the humidity measuring instrument, the output end of the processor is respectively connected to the first flow controller and the second flow controller, the processor is used for calculating the actual water-to-carbon ratio of the fuel gas flowing into the first port, and according to the actual water-to-carbon ratio and the preset water-to-carbon ratio, correspondingly adjust the first flow regulator by controlling the first flow regulator The flow rate of the gas in the shunt pipe and the flow rate of the gas in the second shunt pipe are adjusted by controlling the second flow regulator. 4 . The fuel cell system according to claim 3 , wherein when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.5-2:1, the flow rate of the gas in the first branch pipe is the same as the The ratio of the flow rate of the gas in the second branch pipe is 0.9-4:1. 5 . The fuel cell system according to claim 1 , wherein a cooler is installed at the inlet end of the decarburization and dehydration device. 6 . 6 . The fuel cell system according to claim 1 , wherein the outlet end of the decarburization and dehydration device is further communicated with a purge gas pipe. 7 . 7 . The fuel cell system according to claim 6 , wherein the gas flow rate in the purge gas pipe accounts for 5% to 10% of the gas flow rate discharged from the outlet end of the decarburization and dehydration device. 8 . 8 . The fuel cell system according to claim 1 , wherein the working pressure of the decarburization and dehydration device is 2Mpa˜3Mpa. 9 . 9 . The fuel cell system according to claim 1 , wherein a first pressurizing device is installed at the outlet end of the decarburization and dehydration device. 10 . 10. The fuel cell system according to claim 1, wherein the fuel cell system further comprises: a cathode heat exchanger, the cathode heat exchanger includes a fifth port, a sixth port, a seventh port and an eighth port, the fifth port communicates with the sixth port, and the seventh port communicates with the sixth port Eight ports are in communication, the fifth port is used to pass the oxygen-containing gas, the sixth port is in communication with the cathode air inlet of the fuel cell assembly, and the seventh port is in communication with the cathode of the fuel cell assembly The air outlet is connected. 11. The fuel cell system according to claim 10, wherein a second booster device is installed at the fifth port of the cathode heat exchanger.

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